INJECTION INTO THE CIRCULATION. 



207 



to operation, have been carefully sterilized in the steam 

 sterilizer or in boiling water. The animal must be kept 

 under close observation for about an hour after injec- 

 tion. 



The operation is one that cannot be learned from 

 verbal description. It can only be successfully per- 

 formed after actual practice. 



If the precautions which have been mentioned are 

 observed, but little difficulty in performing the opera- 

 tion will be experienced. 



Its greater convenience and simplicity as compared 

 with other methods for the introduction of substances 

 into the circulation commend it as an operation with 

 which to make oneself familiar. The animals sustain 

 practically no wound, they experience no pain at least 

 they give no evidence of pain and no anaesthesia is 



required. 



FIG. 42. 



Forms of hypodermic syringe . 

 A, Koch's syringe ; B, syringe of Strohschein ; C, Overlack's lorm. 



The form of syringe best suited for this operation is 

 of the ordinary design, but one that permits of thorough 

 sterilization by steam. It should be made of glass and 



